The present invention relates to a frame component which is particularly useful in a three-dimensional (3D) interconnect for a tile transmit/receive (T/R) module.
Tile T/R modules are a variation of radar T/R modules for phase shift antenna applications, and various other devices that transmit and/or receive transmissions over predetermined portions of the electromagnetic spectrum. In a 3D T/R tile module, several circuit components, each of which may include semiconductor material, such as gallium arsenide (GaAs), are connected to each other by an interconnect device which typically comprises an interconnect frame and a plurality of electrical connectors. The electrical connectors need to be insulated from each other, and the module needs to have a ground connection and a shield against electromagnetic interference (EMI). The electrical connectors are typically connected with the circuit components by means of compliant devices such as Fuzz Buttons or Pogo pins, which are well known in the art.
A known interconnect frame in a 3D T/R tile module comprises machined aluminum frame components which are assembled with and support the electrical connectors. The frame components typically include individual passages for the connectors, and a dielectric insert in each connector passage and surrounding the connector in the passage. The aluminum frame components provide the ground connection and EMI shielding for the module.
In forming an aluminum metal interconnect frame, the frame generally requires numerous components (e.g., 22 different types of components) in order to build the interconnect. In addition with GaAs devices, gettering for materials such as hydrogen which can poison the GaAs material is critical, and, as explained in application Ser. No. 09/965,759, traditional gettering techniques have limitations, particularly with regard to the surfaces to which the hydrogen getters can be applied.
It has been suggested that casting an aluminum frame and molding the dielectric inserts can reduce costs. However, such a construction is believed to be significantly more costly than the concept of the present invention. Moreover, an all-metal frame generally provides no compressibility in the frame at the interface of the frame and the other components of the T/R module. This means that extremely precise manufacturing tolerances, and virtually no margin for error, are required to provide effective grounding to such a T/R module.
The present invention provides a new and useful interconnect frame structure for a transmit/receive (T/R) module that transmits and receives electromagnetic radiation over a predetermined portion of the electromagnetic spectrum. The interconnect frame of the present invention is particularly useful in a 3D T/R module, and is designed to be cost effective, and to address the types of issues discussed above in connection with the effective design of such an interconnect frame.
According to the present invention, the interconnect frame comprises at least one frame component formed as a single piece (e.g., as a molded article) from a synthetic resin dielectric material. The frame component is configured to support a plurality of electrical connectors, and has a thin film coating configured to provide a ground connection and EMI shield when the frame structure is incorporated into a transmit/receive module. The dielectric material selection can be tailored for various RF applications by choosing the dielectric constant and loss tangent.
The thin film coating is preferably formed in accordance with U.S. patent application Ser. No. 09/965,759, which application is incorporated herein by reference, and includes (i) a metal layer (e.g., aluminum) that provides a ground connection and EMI shield, (ii) a thin adhesion layer of material (e.g., titanium) between the metal layer and the frame component, (iii) a getter (e.g., a titanium layer in a predetermined thickness) for absorbing hydrogen that can contaminate high performance GaAs devices of a transmit/receive module, and (iv) a palladium layer on top of the getter layer to prevent oxidation of the getter layer while allowing hydrogen to pass through to the getter layer.
According to the present invention, the synthetic resin dielectric material provides the frame component with a range of compressibility such that when the frame component is interfaced with a component of a T/R module, the frame component provides the T/R module with an effective ground connection over that range of compressibility.
According to a preferred embodiment, the frame structure comprises a pair of frame components, each of which has the foregoing structure and configuration, and each of which is configured to support respective portions of each of a plurality of electrical connectors.
Further features of the present invention will be apparent from the following detailed description and the accompanying drawings.